[Zurück]

M. Eisterer, C. Krutzler, M. Zehetmayer, H. W. Weber, S. Kazakov, J. Karpinski:
"Influence of carbon doping on the reversible magnetization of MgB₂ single crystals";
Physica C: Superconductivity and its Applications, 460-462 (2007), S. 606 - 607.

The reversible magnetization of Mg(B1 xCx)2 single crystals with varying carbon content (x = 0-0.095) was measured by SQUID
magnetometry. It was found to be strongly influenced by the two-band character of this material. At low magnetic fields charge carriers
of both bands contribute to superconductivity and to diamagnetism. At high fields the p-band is suppressed and the r-band mainly determines
the magnetization. This allows us to extract information on both bands by analyzing the reversible magnetization in terms of two
band Ginzburg-Landau (GL) theory. The ``intrinsic´´ magnetic penetration increases in both bands with increasing carbon content, but the r-band remains crucial for the upper critical field. Changes in the field dependence of the resulting ``effective´´ penetration depth by carbon doping are discussed.